You're not wrong, but the problem is that interviews aren't actually about jobs. The average person interviews because they need the money. So from the start they're not thinking in the programming space. The pressure for them is to make the interviewer believe they are worthy of the job.

I think if I could describe my personal experiences, I'd say that on a subconscious level, I know that how I speak and articulate details will be observed by the interviewer through a cultural lens more often than not. This may be unique to my personal background, so maybe this is different for other groups. But interviewers often get hung up on the use of different language/terminology, the types of jokes/jests that enter the conversation, how I respond to their language. And there's sometimes been an unwillingness to allow different terminology, perhaps because that's all the interviewer themselves knows and understands.

All that to say, a code interview doesn't always come down to the quality of the code.